UV-absorption measurements are sparse in diesel(-like) combustion, particularly
close to the premixed burn. Thus, such measurements are conducted in diesel-like
jets in a high-pressure vessel in this work, using 1D spontaneous Raman
scattering (SRS) from N2. Stokes (~263 nm) and anti-Stokes (~235 nm)
SRS induced by a krypton fluoride excimer (KrF*) laser (~248 nm) is exploited.
Anti-Stokes SRS can be directly used for attenuation correction of laser-induced
fluorescence (LIF) from NO at ~236 nm. Results show the importance of
attenuation correction, although the jets are largely non-sooting. To identify
absorbers, effects of SRS wavelength, measurement time in the injection event,
location in the flame, jet width (JW), temperature, CO concentration, and
injection pressure are considered. Particularly strong attenuation observed
around the time of second-stage ignition appears to be primarily caused by
combustion intermediates such as partially oxidized fuel. In the quasi-steady
period (QSP) of the injection event, non-negligible contributions of these
absorbers are also found by comparing measured attenuation data to simulated
absorption by hot CO2 and O2. This is particularly
indicated by the wavelength dependence of attenuation. However, the simulations
also show that CO2 appears to be the dominating absorber in the QSP
relatively far away from the premixed burn.